Electric plug



Dec. 11, 1951 J, F, MINARD 2,577,794

ELECTRIC PLUG Filed May 10, 1949 INVENTOR. JOHN F. M 1 NAQD Patented Dec. 11, 1951 UNITED STATE ELECTRIC PLUG John Francis Minard, Mount Vernon, Ohio Application May 10, 1949, Serial No. 92,410

2 Claims.

This invention relates to an electric plug, and more particularly to an electric plug having a novel means for securing the Wires of an electric "cord to the connecting prongs or blades.

It is an object of this invention to provide an electric plug of the kind to be more particularly described hereinafter, formed for ready insertion of the electric wires of a cord and for readily securing the wires to the connecting prongs or blades.

Another object of this invention is to provide an electric plug of this kind having a latch or locking means for securing the wedge terminals in their wire-engaging position to prevent the accidental or inadvertent disengagement of the wires from the terminals.

Still another object of this invention is to provide an electric plug having swingable contact clamping members mounted in the body of the plug for securely clamping the wires to the prongs and a cover member for the plug having depending lugs or arms engageable with the clamping members in their closed position for holding the clamping members or wedges against swinging to an open position, thereby securely holding the wires clamped to the terminals.

With the above and other objects in view, my invention consists in the arrangement, combination and details of construction disclosed in the drawings and specification, and then more particularly pointed out in the appended claims.

In the drawings:

Figure 1 is a top plan view, with the cover removed, showing one of the clamping elements in its'closed, clamping position and the other in I its open, wire-receiving position, the depending members of the cover engageable with the clamping elements in their closed position being shown in dotted lines in clamping engagement with one of the wire-clamping wedges;

Figure 2 is a transverse section taken on the designates generally an electric plug constructed according to an embodiment of this invention, haying a novel means for removably securing the wires of an electric cord to the contact terminals of the electric plug. The wires of the electric cord are adapted to be removably secured to the blades or prongs of the electric plug in a manner whereby the electric wires may be removed or inserted at will, the structure of the electric plug It and a cover member providing for the locking and clamping engagement of the clamping elements, to be described hereinafter, whereby the electric wires are secured clamped in the plug and to their respective prongs or blades.

The electric plug It comprises an insulated cup-shaped body I I, open at its upper end to provide for extension of the connecting prongs or blades I2 and It from the upper open end thereof. The body II is formed with a pair of segmental, arcuate shoulders It on the inside wall thereof for supporting the prongs I2 and I4 in their fixed position within the body.

A contact plate It is fixed to or formed integrally with the lower end of each of the prongs i2 and I4, and as each of the prongs I2 and I4 is formed in substantially the same manner, the description of one of the prongs with its contact plate will suffice for description of the other.

The contact plate It is formed integrally with or otherwise suitably secured to the extreme lower end of the prong I2 and is formed as a segmental, arcuate plate and disposed at right angles to the length of the flat bar II which forms the prong I2. The outer edge I8 of the flat plate I6 line 2-4 of Figure 1, with the cover engaged over the open end of the body;

Figure 3 is a bottom perspective view of the insulated cover removed from the electric plug;

Figure 4 is a bottom perspective view of one of the clamping members removed from the plug;

Figure 5 is a transverse section taken on the line 5-5 of Figure 4;

Figure .6 is an enlarged perspective view of one of the connecting prongs or blades and contact plates'removed from the assembly;'

Figure '7 is a transverse section, on a reduced scale, of an electric plug formed according to an embodiment of this invention, having a wedging member of a modified construction;

Figure 8 is a bottom perspective view of the Referring to the drawings, the numeral I0 is formed on an are substantially the same as the curvature of that portion of the body II with which the outer edge I8 is adapted to be positioned in contact. A hole I9 is formed in the end of the plate I6 adjacent to the lower end of the prong I2 and is provided for the insertion of a fastening element, as a screw or rivet, for securing the plate I5 within the body I I. The body II is formed with a reinforcing strut 2i] terminating downwardly from the extreme upper edge of the upper open end of the body I i. The plate I6 is adapted to be seated, at one end, on the rib 20, and a bolt or rivet, not shown in the drawings, is adapted to be extended through the hole I9 and 'threadably engaged in the strut 20 for fixedly securing the plate It within the body. 1

In Figures 1 and 2 of the drawings, the reinforcing strut 20 is formed integrally with the I In such I2 and clamping plates in the body ll.

A second hole 2! is formed in the plate and is provided for receiving a wire 22 of an electric cord 24. A third hole 25 is formed in the end of the plate It opposite the hole l2 and is provided as a pivot aperture for receiving the pivot pin of a clamping wedge which is pivotally supported on the plate 59. W'hen the prong is used on a plug 15 wherein the upstanding strut extends above the plate I5, as shown'in Figures 1 and 2 of the drawings, andwhere the prong l2 and plate it are secured in the molded body I I, the strut above the plate It will constitute a stop member or lug spaced outwardly from the bar i! of the prong l2 to define a channel 26 through which the wire 22 is engaged, as the wire is led to the clamping element carried by the plate it. is secured in the body H by a bolt or rivet ex- In instances where the plate l5 tending through the aperture is, a separate lug 2'! is fixed to or formed integrally with the plate it on the edge opposite the bar I! to define a channel 28 similar to the channel 25, through which the wire 22 is engaged.

A clamping element 25 is pivotally secured on, a

each of the plates l8 and is formed of a substantially triangular metal or conducting plate 33.

.The plate 32 is formed with a straight longitudinally-extending inside edge 3i and a rightangularly-disposed rear edge 32.

edges 3i and 32, is substantially arcuate in configuration, as clearly shown in Figures 1 and 4 of the drawings, and the rear end portion of the The outside; 5 edge 34, which connects the extremities of the outside edge 34 adjacent the rear edge 32 is up turned to form an upturned guide element for 3 slidably engaging th clamping member 25 over the wire 22 when the clamping element 22 is swung from its open to its closed position. The

closed position of the clamping element as is clearly shown in the upper portion of Figure l of the drawings, and the open position of the other clamping element is shown in the. lower left portion of Figure l. A pivot pin 35 is fixed to or formed on the lower side of the plate 3% at stantially shorter than the length of the clamping plate 16 or contact terminal, and the rear edge 32 of the clamping member 22 is adapted to be slidably engaged in anotch 2'! formed on the lower end of the prong IZ adjacent the plate The clamping members 29 areadapted to be .pivotally secured on their respective clamping plates l6 prior to the installation of the'prongs Upon engagement of the pivot pins as through the holes 25, the lowerends of the pivot pins 35 may be upset, as clearly. shown in Figure 2 of the drawings, for holding the pivots in the holes. The loose engagement of the pivot pin 35 in the aperture 25 provides for a slight vertical swinging movement of the outer edge 32 vertically relative to the inner end or apex of the triangular plate when the clamping member 29 is engaged over the wire 22. In all pivoted positions of the clamping member 29, about the pivot pin 35 thereof, the edge 32 is engaged in the notch 31 in the prong [2. The upper edge 38 of thenotch 31 provides a bearing surface for the upper sideof the clamping member 29 for holding the clamping member against upward movement when 4 the clamping member is slidably engaged over a wire, as the wire 22. A kerf 38 is formed along the upper edge of each of the clamping members 29' transversely thereof, and extending substantially across the pivot pin 35, whereby a screw-driver or similar instrument, may be engaged in the kerf 39 for rotating the clamping element 29 from its open to its closed position "for 'clampingly engaging the wire 22 between the M for closing the upper, open end of the body H.

The cover plate 42 is formed of a disc 44 formed of suitable insulated material having a pair of slots through which the prongs l2. and M are adapted to be freely extended. The outside diameter of the disc 44 is substantially equal to the inside diameter of the upper open end of the body I l, and the lower surface of the disc 44 is adapted to be seated on a peripheral rib or ridge 4 extending about the periphery of the upper open end of the body ll, spaced downwardly a short distance from the upper end ofthe body, as clearly shown in Figure 2 of the drawings. A bridge eieinent ig is fixed to or carried by the lower surface of the disc 4 4 andis formed for holding the wires 22 in spaced-apart relation within the body ll and. for holding the clamping members .29 in their overlying, clamping position relative to the conducting plates IS. The bridging element 48 is substantially. U-shaped in configuration, having a horizontal bight portion as which isadapted to be secured or otherwise fixed to the lower surface of the disc 42 and a pair of depending lugs 56 and 5| for engagement with the longitudinal edges 31: of the clamping members 29 in the clamping position of the clamping members.

In Figures 7 and 8, a pivot pin 52 is fixed to or formed on the contact clamping member 29 slightly different from the pivot pin 36 described above. The pivot pin 52 isformed of an elongated sh-anket which projects substantially at right angles from the lowersurface of the plate 36 and has a forwardly extending horizontal arm 55 on the lower end of the shank: 54. Thepin 52 is not upset in the same manner as the pin 35, since thearm-55 will hold the pivot pin 52 in the hole 25 in the. plate 16. The engagement of the pivot pin 52 through a conducting. and clampin plate it is shown in-Fignre 7 of the drawings, wherein the horizontally-extending arm 55 is disposed below the lower-surface of the plate is, and the horizontalportion 55-acts in substantially the same manner as the upset end of the pin 36 for holding the-plate 29 against accidental or inadvertent upward movement at its pivoted end.

In the use and operation-ofthe electric; plug It, the electric cord 24 is initially extended through an aperture or openingiz56 :inthe-bOttom of the body H with the cover 42: removed. The

wires 22 are. separatediandeach 'of thewires is tivei-toits respective plate [6 for overlying. both the plate and the wire 22 engaged thereon. As

the clamping plate 30 is engaged over the wire 22, the upturned edge 35 will provide for the free sliding of the plate 33 over the wire and the wire will bias the plate 30 upwardly as provided for by the looseness of the pin 36 engaging in the hole 25. The upper edge 38 of the notch 31 will prevent the excessive upward swinging movement of the plate 39, so that when the clamping member 29 is rotated about its pivot pin to put the outside edge 3:3 in engagement with the inside edge of the body ll, the wire 22 will be securely clamped between the clamping member 29 and the underlying contact plate in. The cover 42 is then slid downwardly along the length of the prongs l2 and I4 so that the lugs 50 and 5| extend downwardly below the contact plates l6 on the opposite sides of the body H, and the outside edges of the lugs 5d and 51 engage the longitudinal edges 3i of the clamping members 29 for holding the clamping members against inadvertent or accidental swinging movement about their pivots 35. The engagement of the lugs 59 and 5! of the bridge 48 within the body II with the longitudinal edges 3! of the clamping plates 29 is shown in dotted lines in Figure 1 of the drawmgs.

I do not mean to confine myself to the exact details of construction herein disclosed, but claim all variations falling within the purview of the appended claims.

I claim:

1. A connector plug comprising a cup-shaped insulating body having an open upper end, a contact member having a contact plate fixedly supported within said body and a blade projecting upwardly therefrom and extending upwardly beyond the upper end of the body, a clamping plate loosely pivoted on a vertical axis to said contact plate and arranged to be swung from an inoperative position at one side of said contact plate to an operative position overlying said contact plate to clamp a wire between said contact plate and said clamping plate in which said clamping plate is tilted into parallelism with said contact plate, a cover comprising a disk engageable with the upper end of said body above said clamping plate, said disk being formed with an opening passing said blade, a fixed lug depending from said disk to engage an edge of said clamping plate in the operative position of said clamping plate whereby pivoting of said clamping plate out of operative position is precluded;

2. A connector plug comprising a cup-shaped insulating body having an open upper end, a contact member having a contact plate fixedly supported within said body and a blade projecting upwardly therefrom and extending upwardly beyond the upper end of the body, a clamping plate loosely pivoted on a vertical axis to said contact plate and arranged to be swung from an inoperative position at one side of said contact plate to an operative position overlying said contact plate to clamp a wire between said contact plate and said clamping plate in which said clamping plate is tilted into parallelism with said contact plate, said clamping plate having an upstanding edge arranged to slide on the upper surface of said contact plate as said clamping plate is swung into operative position, said upstanding edge serving to guide a wire into clamping position on said contact plate as said clamping plate is pivoted into operative position.

JOHN FRANCIS MINARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name I Date 1,459,651 Carr June 19, 1923 1,847,246 Hubbell, Jr Mar. 1, 1932 1,984,016 Gisske Dec. 11, 1934 2,027,447 Percy Jan. 14, 1936 

